1. Field of the Invention
The present invention relates to high efficiency, low cost universal direct-vented gas heating units. More particularly, the present invention relates to a multi-purpose horizontal or vertical direct vented gas heating unit having sealed combustion chambers and very high thermal efficiency which conforms to the newly mandated Annual Fuel Utilization Efficiency (AFUE) standards.
2. Description of the Prior Art
Heretofore direct vented zero clearance gas fireplace units were known and have been classified in International Class 1/14. Our U.S. Pat. No. 4,793,322 shows and describes a prefabricated zero clearance direct-vented gas fireplace unit capable of high thermal efficiency and low exhaust stack temperatures. An optional replaceable catalytic conversion unit is installed in the exhaust gas path when it was necessary to reduce carbon monoxide (CO) levels to meet local pollution standards. This prefabricated fireplace unit was manufactured as a horizontal rear vent model and as a vertical top vent model. The two models employ the same mode of operation but require distinctively different parts or elements to complete manufacture in one of the two implementation models.
Our U.S. Pat. No. 4,852,548 shows and describes a free standing universal type fireplace which employs a frame or base structure which is prefabricated. The universal frame is employed on a universal production line to produce a plurality of different type fireplaces by attaching different wall structures to the universal frame. This patent recognizes that the cost of production and inventory is reduced when a production line is tooled for mass production and optimum efficiency.
The present invention comprises an improvement in both of the above mentioned patents in that the present invention fireplace unit is both a top vent (vertical) and a back vent (horizontal) zero clearance fireplace. The novel universal heating unit may also be used as a free standing stove or as an insert for an existing fireplace. Further, the cost of making the present invention universal high thermal efficiency zero clearance fireplace unit has been reduced by requiring a lesser number of structural parts that are designed for low cost manufacturing and low cost automated assembly.
The present invention fireplace provides a structure which can be made from fewer low cost parts and is adapted for precise assembly on a low cost dedicated high efficiency production line.